Method of making a flanged apertured plate



March 20, 1956 A. E. RIGGS 2,738,574

METHOD OF MAKING A FLANGED APERTURED PLATE Filed Dec. 19, 1951 gay. 3

27 -f/ Za IN VEN TOR.

memo/.0 [5. 2/666 BY mm, mm,

HIS HTTOENEYF States atent METiIGD on MAKING A FLANGE-D APERTURED PLATE Arnold E. Riggs}. Andersen, Ind ass'ignor to General otors Corporation, Detroit, Mich., a corporation of Delaware- Application December 19, 1951, Serial No. 262,353

3 Claims. (Cl. 29-545) This invention relates to a new article of manufacture and to a method for making such an article, and particularly to plates for use with electromagnetic devices and to a method for making said plates.

Heretofore it has been the practice to provide a disc or plate of magnetic material for electromagnetic induction apparatus with a central opening to receive a split magnetizable bushing which in turn receives a non-magnetizable tube. This arrangement increases the reluctance leakage of flux path through the plate and bushing.

The prime objects of the present invention are therefore to provide a new and improved apertured plate and a method of forming said plate which includes a flange and an aperture at least partially included in the flange.

In carrying out the above objects it is a further object to provide a method of forming a plate of the character described wherein the magnetic properties of the plate are improved over the prior plates made by other methods.

Amplifying the above object it is a further object to' provide a method of making apertured plates wherein the plates have relatively low reluctance toward the flow of flux when the plates are in use.

Another object of the invention includes the provision of a method of making plates having an integral flange by providing a blank of magnetizable material having a first aperture and a second aperture spaced from each other, drawing the stock surrounding the first aperture into a flange extending outwardly from one of the surfaces of the blank to elongate the second aperture, and then upsetting the flange in the opposite direction for forming a flange on the other side of the blank wherein the upset portion of the flange includes the elongated portion of the second portion therein so that the second aperture will be in the desired position through which lead wires of a coil are passed.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown In the drawing:

Fig. l is a plan view of a metal blank which has been formed according to the first step of the method to be described.

Fig. 2 is a sectional view taken on line 22 of Fig. 1.

Fig. 3 is a plan view of the metal disc showing another step of the method.

Fig. 4 is a sectional view taken on line 4--4 of Fig. 3.

Fig. 5 is a plan view of the blank after an operation following that shown in Fig. 3.

Fig. 6 is a sectional view taken on line 66 of Fig. 5.

Figs. 1 and 2 illustrate the first step in the method. A plate or disc 20 is blanked from a sheet of magnetizable material such as steel. The sheet of metal is passed between suitable dies which operate on the sheet to blank plates or discs 20 having a central aperture 21 and a side aperture 22. The apertures are spaced from each 2 other a distance suflicient to form flanges of required height on opposite faces of the disc.

The nextstep" in the method is to increase: the; di'an're ter: of the opening 21 as shown in Figs. 3 and 4='.- By suitable dies and a; mandrel, not shown, the stock sur= rounding the opening. is forced to one side of= a disc by the mandrel. As thesteel. is cold flowed: to one side of thedisc it flows axially to elongate the opening 22 as at 23 and at the same time form a flange 24. As the mandrel progresses through the opening 21 the opening is increased in size and this metal stock surrounding the first opening will cold flow so that the thickness of the metal forming the flange 24 is less than the thickness of the metal of the main portion of the disc 20. During the formation of the flange 24 the shape of the aperture 22 is distorted into a tear drop shape wherein a portion of the aperture 22 is now included in the flange 24.

In order to provide a second flange on the other face of the disc 20 the flange 24 is upset, as shown in Figs. 5 and 6, by suitable dies and a mandrel, not shown. The diameter of the opening 21, shown in Figs. 3 and 4 remains the same. As the mandrel passes through the opening the metal forming the flange is upset by dies in the opposite direction to form a flange 24a which is less in length than flanges 24 shown in Fig. 4 and a flange 25. The flange 25 is interrupted by the elongated portion 23 of the opening 22. The elongated portion of the opening forms a tapered surface 26 which will assist to facilitate threading lead wires for example, from one side 27 of the disc 20 to the other side 28.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. The method of forming a flanged opening in a plate of magnetizable material having an aperture partially included in the flange and otherwise adjacent thereto comprising the steps, providing a blank of magnetizable material; piercing the blank for providing a first and a second aperture spaced from each other a distance suflicient so that the second aperture is partially included within the wall of a flange to be subsequently formed on the blank; forming a flange by enlarging the first of said apertures in one direction so that the wall of the flange extends beyond the blank between the apertures whereby the second aperture is partially included in the flange; and finally upsetting the flange in the opposite direction for forming a second flange on the opposite side of the blank which second flange includes a portion of the second aperture formerly disposed in said first flange.

2. The method of forming a flanged opening in a plate of magnetizable material having an aperture partially included in the flange and otherwise adjacent thereto comprising the steps, providing a blank of magnetizable material; piercing the blank for providing a first and a second aperture spaced from each other a distance suflicient so that second aperture is partially included with the wall of a flange surrounding said first aperture to be subsequently formed on the blank; forming a flange by enlarging the first of said apertures in one direction so that the wall of the flange extends beyond the blank and between the apertures whereby the second aperture presents an angled relief opening in the wall of the flange; and finally reversing the angle of the angled relief opening in said flange by upsetting the flange to form a second flange at the opposite side of the blank which second mentioned flange includes a portion of the second aperture.

3. The method of forming a double flanged opening in a disc having an angled interruption in one of said flanges comprising the steps; providing a disc having a first opening and a second opening spaced from each other so that the second opening will interrupt a wall of a second flange to be subsequently formed on the disc; forming a first flange by enlarging the first of said openings in one direction so that the wall of the first flange extends beyond the disc between the openings whereby the second opening is elongated and presents an angled relief opening in the first flange; and then upsetting the first flange in the opposite direction for forming a second flange on the other side of the disc wherein the upset portion of the second flange is interrupted by the elongated portion of the second opening that has its angle of relief therein reversed.

References Cited in the file of this patent UNITED STATES PATENTS 1,902,224 Eksergian Mar. 21, 1933 1,926,353 Spatta Sept. 12, 1933 1,929,802 Brauchler Oct. 10, 1933 2,609,596 Clark Sept. 9, 1952 FOREIGN PATENTS 65,235 Denmark Dec. 16, 1946 

